1. Field Of The Invention
The invention relates generally to quenching furnace effluent. More particularly, the invention relates to a process and apparatus for quenching effluent cracked in a furnace using inert solid particles to provide the reaction heat.
2. Description Of The Prior Art
In the technology of thermally cracking hydrocarbon feedstocks to produce olefins, it has long been necessary to stop the reaction of the cracked effluent by rapidly cooling the effluent. Various techniques and apparatus have been provided to facilitate quenching. Both direct quench, wherein a fluid material is introduced directly into the effluent stream, and indirect quench, wherein, heat exchange is performed by heat transfer through the walls separating the hot and cold side of the exchanger are commonly employed. An illustration of the indirect heat exchanger is shown in U.S. Pat. No. 3,583,476 (Herman N. Woebcke et al.).
Processes and equipment have been recently developed to crack hydrocarbons in tubular reactors employing solid-gas contact. The solids are essentially inert particulate materials which are heated to high temperatures and intimately mixed with the hydrocarbon feedstock to provide the heat necessary to crack the hydrocarbon.
The existing solid-gas contact processes employing inert particulate solids to provide the heat necessary for reaction typically separate the particulate solids from the gas before quench occurs. An illustration is seen in patent application Ser. No. 55,148 filed July 6, 1979 (Gartside et al).
However, in the noncatalytic temperature dependant endothermic reaction processes, systems have been developed to quench the entire products stream after the requisite reaction period. The problem is that with heavy feedstocks at high severities, short residence times are desirable. The combination of heavy feedstock, high severity and short residence times impose severe operating problems on the heat recovery devices.